diff --git a/pi/edit_dockerfile.sh b/pi/edit_dockerfile.sh
index 926df5e..d8b2720 100644
--- a/pi/edit_dockerfile.sh
+++ b/pi/edit_dockerfile.sh
@@ -19,22 +19,22 @@ do
     esac
 done
 
-line=$(grep "${DOCKER_REGISTRY}/${PARENT_IMAGE_NAME}:v.*-${PARENT_IMAGE_TYPE}" $DOCKERFILE)
+grep "${DOCKER_REGISTRY}/${PARENT_IMAGE_NAME}:v.*-${PARENT_IMAGE_TYPE}" $DOCKERFILE | while read -r line ; do
+    PI_EXISTING_TAG=$(echo $line | sed 's|FROM ||g' | cut -d ':' -f 2)
+    PI_EXISTING_IMAGE="${DOCKER_REGISTRY}/${PARENT_IMAGE_NAME}:${PI_EXISTING_TAG}"
+    PI_NEW_IMAGE="${DOCKER_REGISTRY}/${PARENT_IMAGE_NAME}:${RELEASE_TAG}-${PARENT_IMAGE_TYPE}"
 
-PI_EXISTING_TAG=$(echo $line | sed 's|FROM ||g' | cut -d ':' -f 2)
-PI_EXISTING_IMAGE="${DOCKER_REGISTRY}/${PARENT_IMAGE_NAME}:${PI_EXISTING_TAG}"
-PI_NEW_IMAGE="${DOCKER_REGISTRY}/${PARENT_IMAGE_NAME}:${RELEASE_TAG}-${PARENT_IMAGE_TYPE}"
+    echo "PI_EXISTING_TAG = $PI_EXISTING_TAG"
+    echo "PI_EXISTING_IMAGE = $PI_EXISTING_IMAGE"
+    echo "PI_NEW_IMAGE = $PI_NEW_IMAGE"
 
-echo "PI_EXISTING_TAG = $PI_EXISTING_TAG"
-echo "PI_EXISTING_IMAGE = $PI_EXISTING_IMAGE"
-echo "PI_NEW_IMAGE = $PI_NEW_IMAGE"
+    echo "Dockerfile before update:"
+    cat ${DOCKERFILE}
+    sed "s|${PI_EXISTING_IMAGE}|${PI_NEW_IMAGE}|g" ${DOCKERFILE} > ${DOCKERFILE}.tmp && mv ${DOCKERFILE}.tmp ${DOCKERFILE}
 
-echo "Dockerfile before update:"
-cat ${DOCKERFILE}
-sed 's|'${PI_EXISTING_IMAGE}'|'${PI_NEW_IMAGE}'|g' ${DOCKERFILE} > ${DOCKERFILE}.tmp && mv ${DOCKERFILE}.tmp ${DOCKERFILE}
-
-echo "sed output:"
-sed 's|'${PI_EXISTING_IMAGE}'|'${PI_NEW_IMAGE}'|g' ${DOCKERFILE}
+    echo "sed output:"
+    sed "s|${PI_EXISTING_IMAGE}|${PI_NEW_IMAGE}|g" ${DOCKERFILE}
+done
 echo "Dockerfile after update:"
 cat ${DOCKERFILE}
 echo "::notice::Dockerfile updated with new image: ${PI_NEW_IMAGE}"
\ No newline at end of file